Transportation Conformity Rule PM2.5, 23024-23043 [E9-11184]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 74, Number 93 (Friday, May 15, 2009)]
[Proposed Rules]
[Pages 23024-23043]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-11184]



[[Page 23023]]

-----------------------------------------------------------------------

Part II





Environmental Protection Agency





-----------------------------------------------------------------------



40 CFR Part 93



Transportation Conformity Rule PM2.5 and PM10 
Amendments; Proposed Rule

Federal Register / Vol. 74, No. 93 / Friday, May 15, 2009 / Proposed 
Rules

[[Page 23024]]


-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 93

[EPA-HQ-OAR-2008-0540; FRL-8904-1]
RIN 2060-AP29


Transportation Conformity Rule PM2.5 and 
PM10 Amendments

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

-----------------------------------------------------------------------

SUMMARY: EPA is proposing amendments to the transportation conformity 
rule that primarily affect conformity's implementation in 
PM2.5 and PM10 nonattainment and maintenance 
areas. EPA is proposing to update the transportation conformity 
regulation in light of the October 17, 2006 final rule that 
strengthened the 24-hour PM2.5 air quality standard and 
revoked the annual PM10 standard. In addition, EPA is 
proposing to clarify the regulations concerning hot-spot analyses to 
address a remand from the Court of Appeals for the District of Columbia 
Circuit (Environmental Defense v. EPA, 509 F.3d 553 (DC Cir. 2007)). 
This portion of the proposal applies to PM2.5 and 
PM10 nonattainment and maintenance areas as well as carbon 
monoxide nonattainment and maintenance areas.
    The Clean Air Act requires federally supported transportation 
plans, transportation improvement programs, and projects to be 
consistent with (``conform to'') the purpose of the state air quality 
implementation plan. DOT is EPA's federal partner in implementing the 
transportation conformity regulation. EPA has consulted with DOT, and 
they concur with this proposed rule.

DATES: Written comments on this proposal must be received on or before 
June 15, 2009, unless a public hearing is requested by May 26, 2009. If 
a public hearing is requested by a commenter, it will be held June 4, 
2009 at the U.S. Environmental Protection Agency, 2000 Traverwood 
Drive, Ann Arbor, Michigan. If a hearing is requested, written comments 
must be received by June 29, 2009.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2008-0540, by one of the following methods:
     www.regulations.gov: Follow the on-line instructions for 
submitting comments.
     E-mail: a-and-r-docket@epa.gov.
     Fax: (202) 566-9744.
     Mail: Air Docket, Environmental Protection Agency, 
Mailcode: 2822T, 1200 Pennsylvania Ave., NW., Washington, DC 20460, 
Attention Docket ID No. EPA-HQ-OAR-2008-0540. Please include a total of 
two copies.
     Hand Delivery: Air Docket, Environmental Protection 
Agency, Mailcode: EPA West Building, EPA Docket Center (Room 3334), 
1301 Constitution Ave., NW., Washington, DC, Attention Docket ID No. 
EPA-HQ-OAR-2008-0540. Please include two copies. Such deliveries are 
only accepted during the Docket's normal hours of operation, and 
special arrangements should be made for deliveries of boxed 
information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2008-0540. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
www.regulations.gov, including any personal information provided, 
unless the comment includes information claimed to be Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Do not submit information that you consider to 
be CBI or otherwise protected through www.regulations.gov or e-mail. 
The www.regulations.gov Web site is an ``anonymous access'' system, 
which means EPA will not know your identity or contact information 
unless you provide it in the body of your comment. If you send an e-
mail comment directly to EPA without going through www.regulations.gov 
your e-mail address will be automatically captured and included as part 
of the comment that is placed in the public docket and made available 
on the Internet. If you submit an electronic comment, EPA recommends 
that you include your name and other contact information in the body of 
your comment and with any disk or CD-ROM you submit. If EPA cannot read 
your comment due to technical difficulties and cannot contact you for 
clarification, EPA may not be able to consider your comment. Electronic 
files should avoid the use of special characters, any form of 
encryption, and be free of any defects or viruses. For additional 
information about EPA's public docket visit the EPA Docket Center 
homepage at https://www.epa.gov/epahome/dockets.htm. For additional 
instructions on submitting comments, go to Section I of the 
SUPPLEMENTARY INFORMATION section of this document.
    Docket: All documents in the docket are listed in the 
www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in www.regulations.gov or in hard copy at the Air and Radiation Docket, 
EPA/DC, EPA West, Room 3334, 1301 Constitution Ave., NW., Washington, 
DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday 
through Friday, excluding legal holidays. The telephone number for the 
Public Reading Room is (202) 566-1744 and the telephone number for the 
Air and Radiation Docket is (202) 566-1742.
    Public Hearing: If a public hearing is requested, it will be held 
at the U.S. Environmental Protection Agency, 2000 Traverwood Drive, Ann 
Arbor, Michigan, on June 4, 2009.

FOR FURTHER INFORMATION CONTACT: Laura Berry, State Measures and 
Conformity Group, Transportation and Regional Programs Division, 
Environmental Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 
48105, e-mail address: berry.laura@epa.gov, telephone number: (734) 
214-4858, fax number: (734) 214-4052; or Patty Klavon, State Measures 
and Conformity Group, Transportation and Regional Programs Division, 
Environmental Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 
48105, e-mail address: klavon.patty@epa.gov, telephone number: (734) 
214-4476, fax number: (734) 214-4052.

SUPPLEMENTARY INFORMATION: The contents of this preamble are listed in 
the following outline:

I. General Information
II. Background on the Transportation Conformity Rule
III. General Overview of Transportation Conformity for the 2006 
PM2.5 NAAQS
IV. Baseline Year for Certain 2006 PM2.5 Nonattainment 
Areas
V. Regional Conformity Tests in 2006 PM2.5 Nonattainment 
Areas That Do Not Have Adequate or Approved SIP Budgets for the 1997 
PM2.5 NAAQS
VI. Regional Conformity Tests in 2006 PM2.5 Areas That 
Have 1997 PM2.5 SIP Budgets
VII. Other Conformity Requirements for 2006 PM2.5 Areas
VIII. Transportation Conformity in PM10 Nonattainment and 
Maintenance Areas and the Revocation of the Annual PM10 
NAAQS
IX. Response to the December 2007 Hot-Spot Court Decision
X. Statutory and Executive Order Reviews

I. General Information

A. Does this Action Apply to Me?

    Entities potentially regulated by the conformity rule are those 
that adopt,

[[Page 23025]]

approve, or fund transportation plans, programs, or projects under 
title 23 U.S.C. or title 49 U.S.C. Regulated categories and entities 
affected by today's action include:

------------------------------------------------------------------------
                Category                 Examples of regulated  entities
------------------------------------------------------------------------
Local                                    Local transportation and air
government.............................   quality agencies, including
                                          metropolitan planning
                                          organizations (MPOs).
State                                    State transportation and air
government.............................   quality agencies.
Federal                                  Department of Transportation
government.............................   (Federal Highway
                                          Administration (FHWA) and
                                          Federal Transit Administration
                                          (FTA)).
------------------------------------------------------------------------

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be affected by this 
proposal. This table lists the types of entities of which EPA is aware 
that potentially could be regulated by the transportation conformity 
rule. Other types of entities not listed in the table could also be 
regulated. To determine whether your organization is regulated by this 
action, you should carefully examine the applicability requirements in 
40 CFR 93.102. If you have questions regarding the applicability of 
this action to a particular entity, consult the persons listed in the 
preceding FOR FURTHER INFORMATION CONTACT section.

B. What Should I Consider as I Prepare My Comments for EPA?

1. Submitting CBI
    Do not submit this information to EPA through www.regulations.gov 
or e-mail. Clearly mark the part or all of the information that you 
claim to be CBI. For CBI information in a disk or CD-ROM that you mail 
to EPA, mark the outside of the disk or CD-ROM as CBI and then identify 
electronically within the disk or CD-ROM the specific information that 
is claimed as CBI. In addition to one complete version of the comment 
that includes information claimed as CBI, a copy of the comment that 
does not contain the information claimed as CBI must be submitted for 
inclusion in the public docket. Information so marked will not be 
disclosed except in accordance with procedures set forth in 40 CFR part 
2.
2. Tips for Preparing Your Comments
    When submitting comments, remember to:
     Identify the rulemaking by docket number and other 
identifying information (subject heading, Federal Register date and 
page number).
     Follow directions--The Agency may ask you to respond to 
specific questions or organize comments by referencing a Code of 
Federal Regulations (CFR) part or section number.
     Explain why you agree or disagree, suggest alternatives 
and substitute language for your requested changes.
     Describe any assumptions and provide any technical 
information and/or data that you used.
     If you estimate potential costs or burdens, explain how 
you arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
     Provide specific examples to illustrate your concerns, and 
suggest alternatives.
     Explain your views as clearly as possible, avoiding the 
use of profanity or personal threats.
     Make sure to submit your comments by the comment period 
deadline identified.
3. Docket Copying Costs
    You may be required to pay a reasonable fee for copying docket 
materials.

C. How Do I Get Copies of This Proposed Rule and Other Documents?

1. Docket
    EPA has established an official public docket for this action under 
Docket ID No. EPA-HQ-OAR-2008-0540. You can get a paper copy of this 
Federal Register document, as well as the documents specifically 
referenced in this action, any public comments received, and other 
information related to this action at the official public docket. See 
the ADDRESSES section for its location.
2. Electronic Access
    You may access this Federal Register document electronically 
through EPA's Transportation Conformity Web site at https://www.epa.gov/otaq/stateresources/transconf/index.htm. You may also access this 
document electronically under the Federal Register listings at https://www.epa.gov/fedrgstr/.
    An electronic version of the official public docket is available 
through www.regulations.gov. You may use www.regulations.gov to submit 
or view public comments, access the index listing of the contents of 
the official public docket, and to access those documents in the public 
docket that are available electronically. Once in the system, select 
``search,'' then key in the appropriate docket identification number.
    Certain types of information will not be placed in the electronic 
public docket. Information claimed as CBI and other information for 
which disclosure is restricted by statute is not available for public 
viewing in the electronic public docket. EPA's policy is that 
copyrighted material will not be placed in the electronic public docket 
but will be available only in printed, paper form in the official 
public docket.
    To the extent feasible, publicly available docket materials will be 
made available in the electronic public docket. When a document is 
selected from the index list in EPA Dockets, the system will identify 
whether the document is available for viewing in the electronic public 
docket. Although not all docket materials may be available 
electronically, you may still access any of the publicly available 
docket materials through the docket facility identified in the 
ADDRESSES section. EPA intends to provide electronic access in the 
future to all of the publicly available docket materials through the 
electronic public docket.
    Public comments submitted on computer disks that are mailed or 
delivered to the docket will be transferred to the electronic public 
docket. Public comments that are mailed or delivered to the docket will 
be scanned and placed in the electronic public docket. Where practical, 
physical objects will be photographed, and the photograph will be 
placed in the electronic public docket along with a brief description 
written by the docket staff.
    For additional information about the electronic public docket, 
visit the EPA Docket Center homepage at https://www.epa.gov/epahome/dockets.htm.

II. Background on the Transportation Conformity Rule

A. What Is Transportation Conformity?

    Transportation conformity is required under Clean Air Act section 
176(c) (42 U.S.C. 7506(c)) to ensure that transportation plans, 
transportation improvement programs (TIPs) and federally supported 
highway and transit project activities are consistent with (``conform 
to'') the purpose of the state air quality implementation plan (SIP). 
Conformity to the purpose of the SIP means that transportation 
activities will not cause new air quality violations, worsen existing 
violations, or delay timely attainment of the relevant national ambient 
air quality standards (NAAQS). Transportation conformity applies to 
areas that are designated nonattainment, and those areas redesignated 
to attainment after 1990 (``maintenance areas'') for transportation-
related criteria

[[Page 23026]]

pollutants: Carbon monoxide (CO), ozone, nitrogen dioxide 
(NO2) and particulate matter (PM2.5, and 
PM10).\1\
---------------------------------------------------------------------------

    \1\ 40 CFR 93.102(b)(1) defines PM2.5 and 
PM10 as particles with an aerodynamic diameter less than 
or equal to a nominal 2.5 and 10 micrometers, respectively.
---------------------------------------------------------------------------

    EPA's transportation conformity rule (40 CFR Parts 51 and 93) 
establishes the criteria and procedures for determining whether 
transportation activities conform to the SIP. EPA first promulgated the 
transportation conformity rule on November 24, 1993 (58 FR 62188), and 
subsequently published several other amendments. DOT is EPA's federal 
partner in implementing the transportation conformity regulation. EPA 
has consulted with DOT, which concurs with this proposed rule.
    A few recent amendments to the transportation conformity rule are 
useful background for today's proposal. In a final rule EPA published 
on July 1, 2004 (69 FR 40004), EPA provided conformity procedures for 
state and local agencies under the 1997 8-hour ozone and 
PM2.5 national ambient air quality standards (NAAQS), among 
other things. EPA's nonattainment area designations for the 1997 8-hour 
ozone and PM2.5 NAAQS were effective in June 2004 and April 
2005 respectively. The July 2004 update provided guidance and rules for 
implementing conformity for these NAAQS. In addition, on May 6, 2005, 
EPA promulgated a final rule entitled, ``Transportation Conformity Rule 
Amendments for the New PM2.5 National Ambient Air Quality 
Standard: PM2.5 Precursors'' (70 FR 24280). This final rule 
specified transportation-related PM2.5 precursors and when 
they must be considered in transportation conformity determinations in 
PM2.5 nonattainment and maintenance areas.
    On March 10, 2006, EPA promulgated a final rule (71 FR 12468) 
entitled, ``PM2.5 and PM10 Hot-Spot Analyses in 
Project-Level Transportation Conformity Determinations for the New 
PM2.5 and Existing PM10 National Ambient Air 
Quality Standards.'' This rule established the criteria and procedures 
for determining which transportation projects must be analyzed for 
local air quality impacts--or ``hot-spots''--in PM2.5 and 
PM10 nonattainment and maintenance areas. See Section IX. of 
today's preamble for more information regarding the March 2006 rule; 
see EPA's Web site at https://www.epa.gov/otaq/stateresources/transconf/index.htm for further information about any of EPA's transportation 
conformity rulemakings.\2\
---------------------------------------------------------------------------

    \2\ At this Web site, click on ``Regulations'' to find all of 
EPA's proposed and final rules as well the current transportation 
conformity regulations.
---------------------------------------------------------------------------

B. Why Are We Issuing This Proposed Rule?

    Today's proposed rule is necessary because EPA promulgated a final 
rule on October 17, 2006 that changed the PM2.5 and 
PM10 NAAQS, as described further below. These revisions to 
the PM2.5 and PM10 NAAQS necessitate an update to 
the transportation conformity rule to provide guidance and rules for 
implementing conformity for these NAAQS. Sections III. through VIII. 
describe the proposed changes to the transportation conformity rule 
that are a result of the October 2006 revisions to the PM2.5 
and PM10 NAAQS.
    Today's proposed rule is also necessary because of a court decision 
regarding the March 2006 hot-spot rulemaking. Section IX. of this 
preamble describes the issue, the court's decision, and EPA's proposed 
response.

III. General Overview of Transportation Conformity for the 2006 
PM2.5 NAAQS

A. Background on 2006 PM2.5 NAAQS Development

    EPA issued a final rule on October 17, 2006 that strengthened the 
24-hour PM2.5 NAAQS and revoked the annual PM10 
NAAQS (71 FR 61144). In that final rule, EPA strengthened the 24-hour 
PM2.5 NAAQS from the 1997 level of 65 micrograms per cubic 
meter ([mu]g/m\3\) (average of 98th percentile values for three 
consecutive years) to 35 [mu]g/m\3\, while the level of the annual 
PM2.5 NAAQS remained unchanged at 15.0 [mu]g/m\3\ (average 
of three consecutive annual average values). This final rule was 
effective on December 18, 2006. EPA selected levels for the final NAAQS 
after completing an extensive review of thousands of scientific studies 
on the impact of fine and coarse particles on public health and 
welfare. For additional information about the October 17, 2006 
rulemaking, the final rule and EPA outreach materials can be found at: 
https://www.epa.gov/air/particlepollution/actions.html.
    The October 2006 rule establishing the 2006 PM2.5 NAAQS 
did not revoke the 1997 annual or 24-hour PM2.5 NAAQS. See 
Section D. below for details on how this proposal would interact with 
conformity requirements for those areas designated nonattainment for 
the 1997 PM2.5 NAAQS.
    EPA signed the final rule designating areas for the 2006 
PM2.5 NAAQS on December 22, 2008. Conformity for the 2006 
PM2.5 NAAQS will apply one year after the effective date of 
the nonattainment designations.\3\ The designations for the 2006 
PM2.5 NAAQS are separate from and do not impact existing 
designations for the 1997 PM2.5 NAAQS.
---------------------------------------------------------------------------

    \3\ The effective date for these nonattainment designations will 
be included in the Federal Register publication of the final 
designations rule.
---------------------------------------------------------------------------

B. When Does Conformity Apply for the 2006 PM2.5 NAAQS?

    Transportation conformity for the 2006 24-hour PM2.5 
NAAQS (``2006 PM2.5 NAAQS'') does not apply until one year 
after the effective date of nonattainment designations for this NAAQS. 
Clean Air Act section 176(c)(6) and 40 CFR 93.102(d) provide a one-year 
grace period from the effective date of designations before 
transportation conformity applies in areas newly designated 
nonattainment for a particular NAAQS.\4\
---------------------------------------------------------------------------

    \4\ EPA began the process of notifying state and local agencies, 
via the EPA regional offices, of the timing of conformity under the 
2006 PM2.5 NAAQS in its April 16, 2007 memorandum 
entitled, ``Transportation Conformity and the Revised 24-hour 
PM2.5 Standard,'' from Merrylin Zaw-Mon, Director, 
Transportation and Regional Programs Division, EPA Office of 
Transportation and Air Quality, to EPA Regional Air Directors, 
Regions I-X.
---------------------------------------------------------------------------

    The following discussion provides more details on the application 
of the one-year grace period in specific types of newly designated 
nonattainment areas for the 2006 PM2.5 NAAQS in 
metropolitan, donut and isolated rural areas. This information is 
consistent with how conformity for new NAAQS has been implemented in 
the past.
1. Metropolitan Areas
    Metropolitan areas are urbanized areas that have a population 
greater than 50,000 and a designated metropolitan planning organization 
(MPO) responsible for transportation planning per 23 U.S.C. 134. The 
one-year grace period means that, in general, within one year after the 
effective date of the initial nonattainment designation for a given 
pollutant and NAAQS, the area's MPO and DOT must make a conformity 
determination with regard to that pollutant and NAAQS for the area's 
transportation plan and TIP. The procedures for interagency 
consultation process found in 40 CFR 93.105 or a state's approved 
conformity SIP must be used in making conformity determinations for 
transportation plans and TIPs. MPOs must continue to meet conformity 
requirements for any other

[[Page 23027]]

applicable NAAQS, including the 1997 PM2.5 NAAQS, if the 
area is designated nonattainment or maintenance for such NAAQS as well.
    The one-year grace period for conformity also applies to project-
level conformity determinations (including hot-spot analyses in certain 
cases) in newly designated 2006 PM2.5 nonattainment areas. 
At the end of the one-year grace period for conformity, requirements 
for project-level conformity determinations must be met for the 2006 
PM2.5 NAAQS before any new federal approvals for such 
projects can occur. For non-exempt Federal Highway Administration 
(FHWA) or Federal Transit Administration (FTA) projects, a conformity 
determination is normally required before the National Environmental 
Policy Act (NEPA) process is completed, since NEPA is typically the 
first stage requiring approval in a federal project's development. 
However, if the NEPA process was completed before conformity applies, 
then areas that are newly designated as nonattainment may also be 
required to demonstrate conformity for subsequent funding and approvals 
for project phases (e.g., right-of-way acquisition, final design, 
construction). Conformity would be needed for a subsequent project 
phase if it occurs after the grace period has ended, and the project 
has not yet been included in a conformity determination for the 
relevant pollutant and NAAQS or met other applicable conformity 
requirements.
    Before the end of the one-year grace period, FHWA or FTA could 
voluntarily choose to make a project-level conformity determination 
that meets the conformity rule's requirements. The procedures for 
interagency consultation found in 40 CFR 93.105 or a state's approved 
conformity SIP must be used in making project-level conformity 
determinations for the 2006 PM2.5 NAAQS. As described 
further below in D. of this section, areas that are designated 
nonattainment for both the 1997 PM2.5 NAAQS and the 2006 
PM2.5 NAAQS will need to address all of these NAAQS in 
conformity determinations.
    If, at the conclusion of the one-year grace period, the MPO and DOT 
have not made a transportation plan and TIP conformity determination 
for the 2006 PM2.5 NAAQS, the area would be in a conformity 
``lapse.'' During a conformity lapse, only certain projects can receive 
additional federal funding or approvals to proceed (e.g., exempt 
projects, project phases that were approved before the lapse). The 
practical impact of a conformity lapse will vary on an area-by-area 
basis. For additional information on projects that can proceed during a 
conformity lapse, read the following guidance memoranda that address 
the March 2, 1999 U.S. Court of Appeals decision that affected related 
provisions of the conformity rule (Environmental Defense Fund v. EPA, 
167 F.3d 641 (DC Cir. 1999): DOT's January 2, 2002 guidance, published 
in the Federal Register on February 7, 2002 (67 FR 5882); DOT's May 20, 
2003 and FTA's April 9, 2003 supplemental guidance documents; and, 
EPA's May 14, 1999 guidance memorandum. EPA's current conformity rule 
reflects all of these guidance documents (69 FR 40005-40006).
2. Donut Areas
    For the purposes of transportation conformity, a ``donut'' area is 
the geographic area outside a metropolitan planning area boundary, but 
inside a designated nonattainment or maintenance area boundary that 
includes an MPO (40 CFR 93.101). The conformity requirements for donut 
areas, including the application of the one-year conformity grace 
period, are generally the same as those for metropolitan areas. Within 
one year of the effective date of an area's initial nonattainment 
designation for the 2006 PM2.5 NAAQS, the existing and 
planned transportation network for the donut portion of the area (as 
well as for the metropolitan portion of the area) must demonstrate 
conformity, or conformity of the metropolitan transportation plan and 
TIP will lapse as described above, and the entire nonattainment area 
will be unable to obtain additional project funding and approvals for 
the duration of the lapse.
    The interagency consultation group for each newly designated 
nonattainment area that includes a donut portion should determine how 
best to consider the donut area transportation system and new donut 
area projects in the MPO's regional emissions analyses and 
transportation plan and TIP conformity determinations. For more 
discussion on how conformity determinations should be made for donut 
areas, see the preamble to the July 1, 2004 conformity rule (69 FR 
40013).
    In nonattainment and maintenance areas with a donut portion, 
adjacent MPOs must meet conformity requirements for the 2006 
PM2.5 and other applicable NAAQS, including requirements for 
any 1997 PM2.5 NAAQS for which the donut area is designated 
nonattainment.
    The one-year grace period for conformity also applies to project-
level conformity determinations in newly designated nonattainment areas 
that include a donut portion, as described above for projects in 
metropolitan areas.
3. Isolated Rural Areas
    Isolated rural nonattainment and maintenance areas are areas that 
do not contain or are not part of any metropolitan planning area as 
designated by 23 U.S.C. 134 and 49 U.S.C. 5303 (40 CFR 93.101). 
Isolated rural areas do not have metropolitan transportation plans or 
TIPs required under 23 U.S.C. 134 and 49 U.S.C. 5303 and 5304 for any 
portion of the area, and do not have projects that are part of the 
emissions analysis of any MPO's transportation plan or TIP. Instead, 
projects in such areas are included only in statewide transportation 
improvement programs and statewide transportation plans, when 
appropriate.
    As in other newly designated nonattainment areas, the one-year 
conformity grace period for the 2006 PM2.5 NAAQS will begin 
on the effective date of an isolated rural area's initial nonattainment 
designation. However, because these areas do not have federally 
required metropolitan transportation plans and TIPs, they are not 
subject to the frequency requirements for conformity determinations on 
transportation plans and TIPs (40 CFR 93.104(b), (c), and (e)). 
Instead, conformity determinations in isolated rural areas are required 
only when a non-exempt FHWA/FTA project(s) needs funding or approval.
    In fact, many isolated rural areas may not have a transportation 
project in need of federal funding or approval for some time after the 
one-year grace period has ended, and therefore, would not have to 
demonstrate conformity before that time. Once the conformity grace 
period has expired, a conformity determination would only be required 
in such areas when a non-exempt FHWA/FTA project needs funding or 
approval. For more information on the conformity requirements for 
isolated rural areas, see 40 CFR 93.109(l); corresponding discussions 
on how to demonstrate conformity in isolated rural areas can also be 
found in the preambles to the November 24, 1993 transportation 
conformity final rule (58 FR 62207) and the August 15, 1997 final rule 
(62 FR 43785).
    Please note that the current regulation's Sec.  93.109(l) would be 
renamed as Sec.  93.109(n) under today's proposal, due to the other 
proposed revisions and additions in this regulatory section. As we are 
simply renumbering this provision, we are not seeking comment because 
it is an administrative change. The basic

[[Page 23028]]

conformity requirements for isolated rural areas remain unchanged.

C. Proposed Definitions for PM2.5 NAAQS

    EPA is proposing two new definitions to Sec.  93.101 of the 
conformity rule to distinguish between the 1997 PM2.5 NAAQS 
and the 2006 PM2.5 NAAQS. These definitions would help 
implement certain conformity requirements in areas that have been 
designated nonattainment for 1997 PM2.5 NAAQS and/or 2006 
PM2.5 NAAQS. Some areas designated nonattainment for the 
2006 PM2.5 NAAQS also are designated nonattainment for the 
1997 PM2.5 NAAQS. In addition, some areas are designated for 
only the 2006 PM2.5 NAAQS.
    The proposed addition of these definitions is also similar to the 
existing rule's definitions in 40 CFR 93.101 for the 1-hour ozone NAAQS 
and 8-hour ozone NAAQS, and the proposed definitions are generally 
consistent with how EPA is defining both kinds of PM2.5 
areas for air quality planning purposes. EPA also notes that any 
provision of the conformity rule that references only 
``PM2.5'' and does not specify which NAAQS will continue to 
apply to any area designated nonattainment for a PM2.5 
NAAQS.

D. How Would This Proposal Interact With Existing Conformity 
Requirements for the 1997 PM2.5 NAAQS?

    Sections IV. through VI. of today's proposal describe proposed 
conformity requirements for areas designated nonattainment for the 2006 
PM2.5 NAAQS. EPA is not proposing any changes to the 
existing transportation conformity requirements for areas designated 
nonattainment for the 1997 PM2.5 NAAQS, since EPA's 
nonattainment designations for the 2006 PM2.5 NAAQS will not 
affect existing 1997 PM2.5 NAAQS nonattainment designations.
    Nonattainment designations for the 1997 and 2006 PM2.5 
NAAQS are different designations with separate SIP requirements, 
different attainment dates, etc. As a result, Clean Air Act section 
176(c)(5) requires conformity requirements to be met in both 1997 and 
2006 PM2.5 nonattainment and maintenance areas, as 
applicable.
    Some areas designated nonattainment for the 2006 PM2.5 
NAAQS have never been subject to PM2.5 conformity 
requirements. Under today's proposal and Clean Air Act section 
176(c)(5), these areas would be required to meet only 2006 
PM2.5 conformity requirements, and not conformity 
requirements for the 1997 PM2.5 NAAQS, because these areas 
are not designated nonattainment for the 1997 PM2.5 NAAQS.
    Other areas designated nonattainment for the 2006 PM2.5 
NAAQS have been designated also, in whole or in part, for the 1997 
PM2.5 NAAQS. These areas would continue to meet their 
existing conformity requirements for the 1997 PM2.5 NAAQS as 
well as any additional requirements for the 2006 PM2.5 
NAAQS.
    EPA notes that MPOs where both the 1997 and 2006 PM2.5 
NAAQS apply would have to determine conformity for both NAAQS. MPOs 
subject to both the 1997 and 2006 PM2.5 NAAQS will be able 
to:
     Use existing transportation models and data for regional 
emissions analyses for both NAAQS, especially where nonattainment area 
boundaries are the same;
     Rely on analysis years for conformity determinations that 
are the same for both NAAQS (e.g., analysis years for the last year of 
the transportation plan, an intermediate year, etc.); and
     Meet consultation and other conformity requirements 
through the existing processes.
    EPA is also proposing that before budgets for the 2006 
PM2.5 NAAQS are available, conformity determinations for 
some 2006 PM2.5 areas would be based on the same conformity 
test (i.e., the budget test) that is being used for the 1997 
PM2.5 NAAQS. As described in Section VI., EPA is proposing 
that MPOs use any adequate or approved SIP budgets for the 1997 
PM2.5 NAAQS for conformity determinations that are made 
prior to SIP budgets for the 2006 PM2.5 NAAQS being 
available.
    Today's proposal does not impact project-level conformity 
requirements for the 1997 PM2.5 NAAQS. For example, EPA is 
not proposing any changes to the PM2.5 hot-spot analysis 
requirements, and EPA and FHWA's existing guidance for such analyses 
continues to be available.\5\ For the purposes of PM2.5 
conformity, a hot-spot analysis must address the PM2.5 NAAQS 
for which the area has been designated nonattainment.\6\ See Section 
VII. for further information regarding EPA's proposal for project-level 
conformity requirements for the 2006 PM2.5 NAAQS.
---------------------------------------------------------------------------

    \5\ ``Transportation Conformity Guidance for Qualitative Hot-
spot Analyses in PM2.5 and PM10 Nonattainment 
and Maintenance Areas,'' EPA420-B-06-902, March 2006.
    \6\ EPA notes that today's proposal does not address project 
requirements for the National Environmental Policy Act or other 
environmental programs.
---------------------------------------------------------------------------

    EPA will work with PM2.5 nonattainment areas as needed 
to ensure that state and local agencies can meet conformity 
requirements for both the applicable 1997 and 2006 PM2.5 
NAAQS in a timely and efficient manner. EPA requests comment on whether 
additional information or training will be necessary for conformity 
implementation under the 2006 PM2.5 NAAQS. If your agency 
submits comments, please be as specific as possible regarding what 
types of situations and issues may need to be addressed in future 
implementation of PM2.5 conformity requirements.

IV. Baseline Year for Certain 2006 PM2.5 Nonattainment Areas

A. Background

    Conformity determinations for transportation plans, TIPs, and 
projects not from a conforming transportation plan and TIP must include 
a regional emissions analysis that fulfills Clean Air Act provisions. 
The conformity rule provides for several different regional emissions 
analysis tests that satisfy Clean Air Act requirements in different 
situations. Once a SIP with a motor vehicle emissions budget 
(``budget'') is submitted for an air quality NAAQS and EPA finds the 
budget adequate for conformity purposes or approves it as part of the 
SIP, conformity is demonstrated using the budget test for that 
pollutant or precursor, as described in 40 CFR 93.118.
    Before an adequate or approved SIP budget is available, conformity 
of the transportation plan, TIP, or project not from a conforming 
transportation plan and TIP is demonstrated with the interim emissions 
test(s), as described in 40 CFR 93.119. The interim emissions tests 
include different forms of the ``build/no-build'' test and ``baseline 
year'' test. In general, for the baseline year test, emissions from the 
planned transportation system or project not from a conforming 
transportation plan and TIP are compared to emissions that occurred in 
the baseline year (please refer to Sec.  93.119 for the more detailed, 
specific requirements). This part of today's proposal would update 
Sec.  93.119 of the current conformity rule for the 2006 
PM2.5 NAAQS. The baseline year for nonattainment areas under 
the 1997 PM2.5 NAAQS is 2002 (40 CFR 93.119(e)(2)). Sections 
V. and VI. of this proposal go into further detail about how any 
baseline year option would be applied in 2006 PM2.5 areas.

[[Page 23029]]

B. Proposal

    EPA is proposing that a year more recent than 2002 be used as the 
baseline year for conformity purposes in 2006 PM2.5 
nonattainment areas. EPA requests comment on the following proposed 
options:
     Option 1: Define the baseline year as 2008;
     Option 2: Rather than naming a specific year, define the 
baseline year for conformity purposes as whatever year would be used to 
meet other air quality planning requirements, such as SIP planning and 
inventory requirements;
     Option 3: Define the baseline year as 2005.
    Option 2 would establish the baseline year for conformity purposes 
for the 2006 PM2.5 nonattainment areas as well as any areas 
designated for a PM2.5 NAAQS that EPA promulgates in the 
future. Therefore, if this option were finalized, the transportation 
conformity rule would not have to be amended in the future to establish 
a new baseline year for conformity if additional NAAQS changes are made 
in the future.
    There are different formulations of regulatory text that EPA could 
use to define the baseline year under Option 2. For example, EPA could 
define the baseline year for any area designated for a PM2.5 
NAAQS promulgated after 1997 as the most recent year for which EPA's 
Air Emissions Reporting Requirements (AERR) (40 CFR part 51) requires 
submission of on-road mobile source emissions inventories, as of the 
effective date of EPA's nonattainment designations for such NAAQS. 
Another possibility would be to simply define the conformity baseline 
year as the year that will be used as the baseline for SIP development 
for given NAAQS, which EPA could specify in a guidance memorandum 
issued in the future.
    Option 2 would likely result in the year 2008 as the baseline year 
in 2006 PM2.5 areas because this is the year anticipated to 
be the baseline year for SIP planning and inventory requirements. The 
year 2008 would also be the most recent year of on-road mobile source 
emissions inventories available for SIP planning purposes when SIPs for 
the 2006 PM2.5 NAAQS are likely to be due.
    EPA is proposing rule language for Options 1 and 2 in Sec.  
93.119(e)(2)(B), although all three of these options could be 
considered for the final rule. EPA is therefore soliciting comment on 
all three options. While today's action proposes no changes to the 2002 
baseline year for areas designated nonattainment for the 1997 
PM2.5 NAAQS, we propose to reorganize Sec.  93.119(e)(2) to 
clarify that 2002 applies only to areas designated nonattainment for 
the 1997 PM2.5 NAAQS.
    The existing interagency consultation process (40 CFR 
93.105(c)(1)(i)) would be used to determine the latest assumptions and 
models for generating baseline year motor vehicle emissions to complete 
any baseline year test. The baseline year emissions level that is used 
in conformity would be required to be based on the latest planning 
assumptions available, the latest emissions model, and appropriate 
methods for estimating travel and speeds as required by 40 CFR 93.110, 
93.111, and 93.122 of the current conformity rule. The baseline year 
test can be completed with a submitted or draft baseline year motor 
vehicle emissions SIP inventory, if the SIP reflects the latest 
information and models. If such a SIP baseline is not available, an 
MPO, in consultation with state and local air agencies, could also 
develop baseline year emissions as part of the conformity analysis.

C. Rationale

    EPA believes that a more recent year than 2002 is appropriate for 
meeting Clean Air Act conformity requirements for 2006 PM2.5 
nonattainment areas. EPA also believes that using a more recent year 
than 2002 is required to meet these statutory requirements, and is more 
environmentally protective and relevant for the 2006 PM2.5 
NAAQS.
    Coordinating the conformity baseline year with the year used for 
SIP planning and an emission inventory year was EPA's rationale for 
using 2002 as the baseline year for conformity tests in existing 
PM2.5 nonattainment areas for the 1997 NAAQS. As described 
in the July 1, 2004 final rule (69 FR 40015), EPA selected 2002 as the 
conformity baseline year because 2002 was identified as the anticipated 
emission inventory base year for the SIP planning process under the 
1997 PM2.5 NAAQS.\7\ EPA continues to believe that 
coordinating the conformity's baseline with other data collection and 
inventory requirements would allow state and local governments to use 
their resources more efficiently. However, for the 2006 
PM2.5 nonattainment areas, the year 2002 does not have the 
same relevance and does not provide the same level of environmental 
protection as a more recent year.
---------------------------------------------------------------------------

    \7\ Also, the AERR requires submission of point, nonpoint, and 
mobile source emissions inventories every three years, and 2002 was 
one of those required years for such updates.
---------------------------------------------------------------------------

    In choosing the baseline year for the 2006 PM2.5 NAAQS, 
EPA also believes it could be important to coordinate the conformity 
rule's baseline year with the year ultimately used as a baseline for 
SIP planning for the 2006 PM2.5 NAAQS as well as other 
emissions inventory requirements. EPA has proposed 2008 as a baseline 
year for conformity purposes (Option 1) and believes such an option 
would be appropriate to meet Clean Air Act conformity requirements. EPA 
selected 2002 for the baseline year tests in 1997 8-hour ozone and 
PM2.5 nonattainment areas in the July 1, 2004 final rule (69 
FR 40015) not only because EPA believed that 2002 was the most 
appropriate measure for meeting Clean Air Act conformity requirements 
not to worsen air quality or delay timely attainment or achievement of 
any required interim milestone prior to SIP budgets being established, 
but also because EPA believed it was important to have transportation 
and air quality planning coordinated. Having consistent baseline years 
for SIPs, conformity determinations and other emissions inventory 
requirements helps to achieve this goal.
    Alternatively, EPA has also proposed 2005 as a baseline year for 
conformity purposes (Option 3) because this year is also relevant for 
2006 PM2.5 areas. The year 2005 is more recent than 2002, 
and 2005 data would also be available for other inventory purposes such 
as the AERR. In addition, most 2006 PM2.5 areas will be 
designated nonattainment based in part on air quality monitoring data 
from the year 2005. EPA is required to make nonattainment designations 
for PM2.5 based on the most recent three years of air 
quality data, i.e., 2005-2007 data for most 2006 PM2.5 
areas. For this reason, 2005 is being proposed as a baseline year for 
conformity purposes.
    Whereas Options 1 and 3 would apply specifically to the 2006 
PM2.5 NAAQS, EPA proposes in Option 2 to generalize the 
language for the baseline year for areas designated under any 
PM2.5 NAAQS established after 1997. Given that the Clean Air 
Act requires EPA to review the NAAQS for possible revision once every 
five years, adopting Option 2 would standardize the process for 
selecting an appropriate baseline year to use in meeting conformity 
requirements before SIP budgets have been established for any future 
PM2.5 NAAQS. This would enable EPA, MPOs and other 
transportation planners to identify the appropriate baseline year for 
conformity purposes without EPA having to amend the conformity 
regulation first.
    In other words, Option 2 would allow EPA to identify an appropriate 
baseline

[[Page 23030]]

year in an expeditious manner for transportation conformity purposes. 
As a result, MPOs and other transportation planners would understand 
conformity requirements for future PM2.5 NAAQS revisions 
more quickly, which may, in turn, also allow more time to prepare and 
complete necessary conformity determinations.
    EPA believes that Option 2 would result in an appropriate baseline 
year for a given PM2.5 NAAQS. Since Option 2 is based on the 
same criteria that have been used for proposed Option 1 and for 
establishing baseline years for other NAAQS (58 FR 62191, 69 FR 40014), 
EPA believes this option would also result in an environmentally 
protective and legal baseline year for conformity under the 2006 
PM2.5 NAAQS and any future PM2.5 NAAQS revisions. 
Finalizing Option 2 would most likely result in a baseline year of 2008 
for the 2006 PM2.5 NAAQS.
    If the regulatory text for this option referred to the AERR 
requirement, the option would ensure that areas designated 
nonattainment for the 2006 PM2.5 NAAQS, as well as areas 
designated for revised PM2.5 NAAQS in the future, would use 
the year for which the most recent emissions inventories are required 
to be submitted as of the effective date of EPA's final designations. 
The regulatory text for Option 2 could also be written to refer to the 
year that will be used as the baseline year for SIP development for a 
given PM2.5 NAAQS.
    In either case, under Option 2 EPA would most likely clarify what 
year is to be used for the baseline year test by issuing a memorandum. 
If this option were finalized, EPA would issue such a memorandum prior 
to conformity requirements applying.
    EPA requests comment on all of these options. Though commenters can 
simply express a preference, providing rationale for a preference is 
especially useful to EPA. In particular, EPA seeks comment on whether 
state and local agencies believe that establishing the baseline year 
using Option 2 presents any implementation concerns, and if so, how EPA 
could address such concerns.

V. Regional Conformity Tests in 2006 PM2.5 Nonattainment 
Areas That Do Not Have Adequate or Approved SIP Budgets for the 1997 
PM2.5 NAAQS

    This part of the proposal discusses regional conformity tests for 
nonattainment areas for the 2006 PM2.5 NAAQS that do not 
have adequate or approved PM2.5 SIP budgets for the 1997 
NAAQS. This proposal would apply to 2006 PM2.5 nonattainment 
areas that were not covered by the 1997 PM2.5 NAAQS, as well 
as nonattainment areas for both PM2.5 NAAQS that do not have 
an adequate or approved 1997 PM2.5 SIP budget. EPA would 
address conformity tests for these areas under proposed section 
93.109(j) of the conformity rule. See Section VI. of today's proposal 
for conformity tests in 2006 PM2.5 areas that have adequate 
or approved SIP budgets for the 1997 PM2.5 NAAQS.
    Note that this section of the preamble proposes new requirements 
for conformity only under the 2006 PM2.5 NAAQS. This 
proposal does not address the requirements for demonstrating conformity 
for the 1997 PM2.5 NAAQS.

A. Conformity After 2006 PM2.5 SIP Budgets Are Adequate or Approved

1. Proposal
    Once a SIP for the 2006 PM2.5 NAAQS is submitted with a 
budget(s) that EPA has found adequate or approved, EPA proposes that 
the budget test must be used in accordance with 40 CFR 93.118 to 
complete all applicable regional emissions analyses for the 2006 
PM2.5 NAAQS. Conformity would be demonstrated if the 
transportation system emissions reflecting the proposed transportation 
plan, TIP, or project not from a conforming transportation plan and TIP 
were less than or equal to the motor vehicle emissions budget level 
defined by the SIP as being consistent with Clean Air Act requirements.
    The first SIP for the 2006 PM2.5 NAAQS could be a 
control strategy SIP required by the Clean Air Act (i.e., reasonable 
further progress SIP or attainment demonstration) or a maintenance 
plan. States could also voluntarily choose to submit an ``early 
progress SIP'' prior to required SIP submissions. Early progress SIPs 
must demonstrate a significant level of future emissions reductions 
from a previous year's emissions. For example, an area could submit an 
early progress SIP for the 2006 PM2.5 NAAQS that 
demonstrates a specific percentage of emissions reductions (e.g., 5-
10%) in an area's attainment year from the baseline year emissions 
(e.g., 2008). An early progress SIP would include emissions inventories 
for all emissions sources for the entire 2006 PM2.5 
nonattainment area and would meet applicable requirements for 
reasonable further progress SIPs. EPA has discussed this option in past 
conformity rule preambles, e.g., the July 1, 2004 transportation 
conformity final rule (69 FR 40028), and many states have established 
early progress SIP budgets for conformity purposes.
    Whatever the case, the interim emissions test(s) would no longer be 
used for direct PM2.5 or a relevant precursor once an 
adequate or approved SIP budget for the 2006 PM2.5 NAAQS is 
established for the pollutant or precursor. EPA encourages states to 
develop their future 2006 PM2.5 SIPs in consultation with 
MPOs, state and local transportation agencies, and local air quality 
agencies to facilitate future conformity determinations. Once EPA's 
nonattainment designations are finalized, EPA Regions would be 
available to assist states in the development of early progress SIPs 
for the 2006 PM2.5 NAAQS, if desired.
2. Rationale
    EPA believes that this proposal meets statutory requirements for 
conformity determinations that occur after SIP budgets are available 
for the 2006 PM2.5 NAAQS. Section 176(c) of the Clean Air 
Act states that transportation activities must ``conform to an 
implementation plan * * * '' (SIP) and states further that conformity 
to an implementation plan means conformity to the SIP's purpose. Once 
EPA finds a budget for the 2006 PM2.5 NAAQS adequate or 
approves the SIP that includes it, the budget test provides the best 
means to determine whether transportation plans and TIPs meet the 
statutory obligations in Clean Air Act sections 176(c)(1)(A) and (B) 
for that NAAQS. That is, the budget test best shows that transportation 
plans and TIPs conform to the SIP's purpose of eliminating or reducing 
the severity and number of violations of the NAAQS and achieving 
expeditious attainment of the NAAQS (176(c)(1)(A)); and best confirms 
the requirement that transportation plans and TIPs not cause or 
contribute to any new violation, worsen an existing violation, or delay 
timely attainment or any required interim milestone (176(c)(1)(B)). The 
budget test also best demonstrates that transportation plans and TIPs 
comply with the statutory obligation to be consistent with the 
emissions estimates in SIPs, according to Clean Air Act section 
176(c)(2)(A). By being consistent with the on-road mobile source 
emissions levels in the SIP, transportation planners can ensure that 
their activities remain consistent with state and local air quality 
goals to protect public health.

B. Conformity Before 2006 PM2.5 SIP Budgets Are Adequate or Approved

1. Proposal
    EPA is proposing that these 2006 PM2.5 nonattainment 
areas meet one of the following interim emissions tests for

[[Page 23031]]

conformity determinations conducted before adequate or approved 2006 
24-hour PM2.5 SIP budgets are established:
     The build-no-greater-than-no-build test (``build/no-build 
test''), or
     The no-greater-than-baseline year emissions test 
(``baseline year test'').
    Again, this part of the proposal would apply only in cases where a 
2006 PM2.5 area does not have adequate or approved SIP 
budgets for either the 2006 or 1997 PM2.5 NAAQS. Section VI. 
of the proposal covers the case where a 2006 PM2.5 
nonattainment area has a SIP budget for the 1997 PM2.5 
NAAQS.
    This proposal is similar to the transportation conformity rule at 
40 CFR 93.119(e) for nonattainment areas for the 1997 PM2.5 
NAAQS. Today's proposal would allow 2006 PM2.5 nonattainment 
areas without SIP budgets to choose between the two interim emissions 
tests, rather than require that one specific test or both tests be 
completed. Conformity would be demonstrated under the proposal if the 
transportation emissions reflecting the proposed transportation plan or 
TIP (build) were less than or equal to either the emissions from the 
existing transportation system (no-build), or the level of motor 
vehicle emissions in the baseline year, as described in 40 CFR 93.119. 
A full discussion of the proposed baseline year options for the 2006 
PM2.5 NAAQS can be found in Section IV. of today's notice.
2. Rationale
    EPA believes that this proposal meets statutory requirements for 
conformity determinations that occur before SIP budgets are available 
for the 2006 PM2.5 NAAQS. EPA believes it is appropriate to 
provide flexibility and allow 2006 PM2.5 areas to meet only 
one interim emissions test before adequate or approved PM2.5 
SIP budgets are established. This proposal meets statutory requirements 
and parallels the current rule's requirements for 1997 PM2.5 
nonattainment areas (69 FR 40028-40031), which were upheld by an 
October 2006 court decision. Environmental Defense v. EPA, 467 F.3d 
1329 (DC Cir. 2006).\8\ In addition, this proposal is consistent with 
past rulemakings for interim emissions test requirements for other 
pollutants, as described below.
---------------------------------------------------------------------------

    \8\ Petitioners challenged several aspects of the conformity 
regulations. In its decision, the U.S. Court of Appeals for the 
District of Columbia Circuit upheld EPA's regulations at 40 CFR 
93.119(b)(2), (d), and (e) ``because the Act does not require that 
activities involving transportation actually reduce pollutants, but 
merely not frustrate an implementation plan's purpose to reduce 
overall emissions.'' The court also upheld EPA's regulations at 40 
CFR 93.118(b), (d), and (e)(6). The court vacated a narrow provision 
at 40 CFR 93.109(e)(2)(v) which had allowed 8-hour ozone areas to 
avoid using their existing 1-hour budgets under certain 
circumstances. This provision was removed from the transportation 
conformity regulation in the January 24, 2008 final rule.
---------------------------------------------------------------------------

    Using either the build/no-build test or baseline year test is 
sufficient to meet Clean Air Act section 176(c)(1)(B) requirements that 
transportation activities do not cause new air quality violations, 
worsen existing violations, or delay timely attainment or achievement 
of interim reductions or milestones. The baseline year and the build/
no-build tests are sufficient for demonstrating conformity when an area 
does not have a SIP budget for a portion of a nonattainment area.
    Based on the Clean Air Act, EPA has previously determined that only 
ozone and CO areas of higher classifications \9\ are required to also 
satisfy section 176(c)(3)(A)(iii) requirements during the time period 
before adequate or approved SIP budgets are available (58 FR 3782-3783; 
62 FR 43784-43785; 69 FR 40018, 40019-40031). As a result, the current 
rule requires these ozone and CO areas to meet both interim emissions 
tests, rather than only one test.
---------------------------------------------------------------------------

    \9\ That is, ozone areas classified as moderate and above, and 
CO areas classified as moderate with design value greater than 12.7 
ppm and serious.
---------------------------------------------------------------------------

    However, the current conformity rule already allows areas 
designated for the other pollutants, as well as the lower 
classifications of ozone and CO, to conform based on only one interim 
emissions test, rather than having to complete two tests and thereby 
contribute further reductions towards attainment. EPA proposes that the 
2006 PM2.5 areas also be required to meet only one of the 
interim emissions tests to meet the Clean Air Act's requirements in 
section 176(c)(1)(B). For more information and the full rationale for 
allowing some areas to conform based on only one interim emissions 
test, see the November 24, 1993 final rule (58 FR 62197) that addressed 
interim requirements for PM10 and NO2 areas, and 
the July 1, 2004 final rule (69 FR 40029) that established interim 
requirements for 1997 PM2.5 areas.
    EPA believes that the no-greater-than-baseline year interim 
emissions test is an appropriate test for meeting section 176(c)(1)(B) 
requirements in 2006 PM2.5 nonattainment areas. By 
definition, the no-greater-than baseline year test ensures that 
emissions from on-road mobile sources are no greater than they were 
during the baseline year that will most likely be used for 2006 
PM2.5 NAAQS SIP planning purposes. If future on-road 
emissions do not increase above their base year levels, applicable 
statutory requirements are met.
    Finally, the build/no-build test would also allow a 2006 
PM2.5 area to meet statutory requirements. As described 
above, the build/no-build test requires a regional emissions analysis 
to demonstrate that the emissions from the transportation system in 
future years, if it included the proposed action and all other expected 
regionally significant projects, would be less than the emissions from 
the current transportation system in future years. Since a new 
transportation plan, TIP, or project (in the build scenario) could not 
result in regional emissions that are higher than those that would 
occur in the absence of new transportation activities (in the no-build 
scenario) for the system, the Clean Air Act section 176(c)(1)(B) 
requirements are met. For these reasons, EPA believes that the build/
no-build test continues to be an appropriate interim test prior to SIP 
budgets being available.

C. General Implementation of Regional Tests

    This proposal would apply the existing conformity rule's general 
requirements for PM2.5 regional emissions analyses in 2006 
PM2.5 areas that do not have adequate or approved SIP 
budgets for the 1997 PM2.5 NAAQS. EPA is including this 
discussion of the existing regulation's requirements for clarity, to 
help readers understand how the existing regulation would apply to 
areas designated nonattainment for the 2006 PM2.5 NAAQS. 
However, EPA is not soliciting comment on these existing requirements 
that we are not proposing to change. The following examples are 
intended to illustrate how today's proposal would be implemented in 
practice for 2006 PM2.5 areas without adequate or approved 
1997 PM2.5 SIP budgets.
1. Decisions Made Through the Interagency Consultation Process
    The existing rule's consultation process would be used to determine 
the test for completing any regional emissions analysis for the 2006 
PM2.5 NAAQS, as required by 40 CFR 93.105(c)(1)(i). The 
existing interagency consultation process would also be used to 
determine the latest assumptions and models for generating motor 
vehicle emissions regardless of the test used. Refer to Section IV. of 
this preamble for details about generating baseline year emissions if 
that interim emissions test is selected for a given conformity 
determination.
    The consultation process would also be used to determine which 
analysis

[[Page 23032]]

years should be selected for regional emissions analyses. Before an 
adequate or approved 2006 PM2.5 budget is available, areas 
would be able to choose, through interagency consultation, either 
interim emissions test for each conformity determination. However, the 
same test would be required to be used for each analysis year for a 
given determination. EPA believes that sufficient flexibility exists 
without mixing and matching interim emissions tests for different 
analysis years within one conformity determination, which is 
unnecessarily complicated and may indicate that an area would not 
conform using one test consistently.
2. General Conformity Test Requirements for All Areas
    Regional emissions analyses under this proposal would be 
implemented through existing conformity requirements such as 40 CFR 
93.118, 93.119, and 93.122. For example, the existing conformity rule 
requires that only certain years within the transportation plan (or 
alternate timeframe) be examined. Under 40 CFR 93.118(d), the following 
years would be analyzed for the